IGo batteries are alkaline 1.5V, not nicad or nimh, which are only 1.2V.
They claim that they retain their charge, as supplied, for 8 years, I am not going to wait that long !
My outdoor weather station has AA versions of these, performed well in freezing temperatures.
These were purchased for a small label printer, work ok.
For 12V, 8 alkaline batteries, or 10 nicad or nimh.
I have several iGo alkaline batteries and chargers.